Intermediates of the plant biosynthesis of morphine, including (-)-salutaridine, (-)-reticuline and (-)-norreticuline were prepared by known procedures, the compounds characterized and delivered for study of their bioconversion in brain tissues. Synthesis of natural (-)-salutaridine was accomplished from thebaine by Rapoport procedure, affording first 6-0-demethylsalutaridine. Conversion of the former into salutaridine was accomplished by a process developed by Hungarian scientist by first acetylating the phenolic units, partial hydrolysis of the 6-acetoxy group, followed by 0-methylation with diazomethane, and deacetylation of the C-4 acetoxy group.